It is desirable in many gas sensor instrument applications to have available a safe and reliable source of chlorine gas. Normally such instruments and their associated gas source are portable, thus they must be constructed to suitably withstand the mechanical shocks often encountered by portable instrumentation apparatus. It has been conventional practice to supply gas to these portable instruments by either mounting a replaceable gas flask in the instrument housing (or in associated holder means), or by providing the gas from a large fixed system and then diluting the chlorine gas with a suitable dilutant such as nitrogen by mixing it in a system that typically includes a series of pressure reducers, valves and flow meters that are operable to selectively meter the chlorine into a gas sample that is subsequently fed into an associated instrument at a desired flow rate. These kinds of conventional sources of chlorine gas for instrumentation purposes have been found to be generally effective for the purposes intended, but they involve several drawbacks that it would be desirable to avoid, if possible. For example, since a large supply of pressurized chlorine is necessarily available at all times in such conventional systems, there constantly exists a risk of escape of dangerous chlorine gas into the atmosphere. Such escape of gas can occur from a number of causes ranging from an inadvertent opening of the pressurized system to an accidentally caused leak or rupture developing in the system due to mishandling. In any case, the hazard is always present, even when the instrumentation system is not is use, since the system is, by its nature, constantly pressurized.
A further disadvantage of such relatively complex prior art systems is that the corrosive nature of chlorine gas makes it necessary to construct the component parts of the system from corrosion-resistant materials. The complexity of these systems and the associated costs of corrosion-resistant materials makes the overall expense of many such systems prohibitive. A further complicating factor often encountered in instrumentation applications for chlorine gas is that the gas must be moistened before it is suitable for given instrumentation uses; thus, it is often necessary to provide separate humidifying means to moisten the chlorine gas after it leaves its pressurized storage container, before it is introduced to the associated instrumentation. Again, the expense associated with providing the necessary corrosion-resistant components for these needed humidifier systems is undesirable and should be avoided if possible.